Convertible reed contact relay



J1me 1965 J. N. PEARSE ETAL CONVERTIBLE REED CONTACT RELAY Filed May 6, 1963 3 Sheets-Sheet 2 INVENTORS JAMES N- PEARSE JOSEPH C. MAYER 'III'II'IIIIIIIIIIIIIIIIIIII/ AT TOR NEY June 1965 J. N. PEARSE ETAL CONVERTIBLE REED CONTACT RELAY 3 Sheets-Sheet 3 Filed May 6, 1963 i ll' INVENTORS JAMES N. PEARSE JOSEPH C.MAYER AT TOR N EY United States Patent 0 3,196,985 CONVERTIBLE REED CONTACT RELAY James N. Pearse, Mcnomonee Falls, and Joseph C. Mayer, Milwaukee, Wis., assignors to Allen-Bradley Company, Milwaukee, Win, a corporation of Wisconsin Filed May 6, 1963, Ser. No. 278,975 6 (Ilairns. (Cl. 200-87) This invention relates to relays which utilize switches with magnetically operable contacts, such as dry reed switches; and it more particularly resides in a relay that is convertible between various manners of operation, such as normally open, normally closed, and latched, and includes a switch; an operating coil for operating the switch; magnetic bias means operable to bias the switch contacts; and means to move the magnetic bias means between inactive and biasing positions with respect to the switch.

Relays having one or more dry reed switches as switching elements are useful for a multitude of switching applications. Because the reed switches are hermetically sealed and fast acting, such relays are especially suitable for applications in which high speed and reliability are critical, such as automatic control and computer circuits. This invention is particularly suited fora relay utilizing dry reed switches, but is also well suited for relays utilizing other sealed contact devices, such as mercury wetted contact tubes, or any other suitable form of switch with magnetically operable contacts.

Relays of the type referred to above often include several, for example four, electrically independent switches mounted in a bobbin on which is wound a common operating coil for the switches. In the case of a four pole relay, one that utilizes four switches, one or perhaps two of the switches are utilized for control purposes while the others are available for connection into external circuits. Many arrangements are, of course, possible and although a four pole relay will be shown and described herein, the number of poles or switches or the manner of their connection in control or controlled circuits forms no part of the invention as such.

Dry reed switches include overlapping, spaced resilient reed contacts, and, like most switches of this type, usually have a normally open form of operation, although normally closed varieties are available. In many applications, however, it is desirable to use supplementary magnetic devices to provide an altered manner of operation. For example, a small additive magnet may be used to hold the contacts of the switch closed or latched after a closing current through an operating coil has ceased, a reverse pulse then being necessary to clear or open the switch.

Although supplementary magnetic devices have been used in the past, they have been used primarily as latching means to affect permanently the operation of a switch. That is, for example, a supplementary magnet is assembled with the relay so that a switch therein always has a latched manner of operation. It is the general object of this invention, on the other hand, to provide a relay in which one or more of any reasonable number of switches can be converted between various manners of operation, such as normally open, normally closed, and latched.

It is another object of this invention to provide a conivertible relay in which conversion is accomplished simply and efliciently by movement of magnetic bias means.

It is a further object of the invention to provide a relay having sturdy, easily operated and effective means for moving the magnetic bias means and holding the same in a desired position.

It is still another object of this invention to provide a relay in which any one or more of a cluster of switches ill 3,li3,%5 Patented June 22, 1965 'ice.

may readily be independently converted between various manners of operation.

It is a still further object of the invention to provide an enclosed relay in which the state of each of a cluster of switches is visually indicated.

It is still another object of this invention to provide a relay comprising a cluster of switches in which each switch is effectively isolated, electrically and magnetically, from its companion switches.

It is a still further object of this invention to provide a relay having a cluster of switches and magnetic bias means for each, wherein the magnetic bias means are shielded from each other and from a common operating coil for the switches.

It is still another object of this invention to provide a relay in which internal and external connections for an operating coil and a number of switches may be easily made.

It is a still further object of this invention to provide a relay including a bobbin and an operating coil mounted by a support which also serves to complete a magnetic return circuit about the coil.

It is still another object of this invention -to provide a relay case construction which serves to enclose, protect, guide and locate various relay elements.

It is a still further object of the invention to provide a relay construction in which various elements are supported by a cover member for insertion into and removal from a case as a unit.

It is still another object of this invention to provide a convertible relay that complies in all respects, such as terminal spacing and the like, with NEMA standards for industrial use.

It is a still further object of this invention to provide a relay with the foregoing and other advantages which is still relatively easy and inexpensive to manufacture and assemble.

()ther objects and advantages will appear from the description to follow. In the description, reference is made to the accompanying drawings in which there is shown, by way of illustration and not of limitation, a preferred embodiment of the invention.

In the drawings:

FIG. 1 is a front view in elevation, with parts broken away and in cross-section, showing a four pole relay formed according to this invention,

FIG. 2 is a top plan view of the relay of FIG. 1,

FIG. 3 is a View in cross-section, with portions of switches therein shown rotate-d ninety degrees from their actual positions, of the relay of FIG. -1 taken along the plane 33 shown in FIG. 2,

FIG. 4- is a view in cross-section of the relay of FIG. 1 taken along the plane 4-4 shown in FIG. 2,

FIG. 5 is a view in cross-section of the relay of FIG. 1 taken along the plane 55 shown in FIG. 3,

FIG. 6 is a View in cross-section of the relay of FIG. 1 taken along the plane -6fi shown in FIG. 3,

FIG. 7 is a view in a cross-section of the relay of FIG. 1 taken along the plane ';'-'--7 shown in FIG. 3,

FIG. 8 is a view in cross-section of the relay of FIG. 1 taken along the plane 8-8 shown in FIG. 3,

FIG. 9 is a view in cross-section of the relay of FIG. 1 taken along the plane 9-9 shown in FIG. 3, and

FIG. 10 is an exploded view in perspective, with parts shown broken away and in cross-section, showing the operating elements of the relay of FIG. 1.

Referring again to the drawings, it can be seen that the relay of the invention is housed in and protected by an enclosure comprising a tubular sheet metal case 1 having a generally square cross-section, a base 2 and a terminal bearing cover 3. The edges of the facing surfaces of the base 2 and cover 3 are recessed so that these 3 elements fit into the open ends of the case 1 to provide a secure, properly oriented flush assembly.

A pair of long bolts 4 have their heads recessed at opposite corners of the cover 3 and extend downwardly along opposite interior corners of the case 1, passing through the base of a bobbin and coil support as will be described, to pass through apertures in the base 2. Hexagonal nuts 5, recessed in sockets formed at the underside of the base 21, receive threaded ends of the bolts 4 to hold the case 1, base 2, and cover 3 together. Not only does this construction provide for simple, effective assembly, but it allows for the cover 3, with a number of operating elements of the relay suspended therefrom as will be described to be inserted into and removed from the case 1 as a unit.

The base 2 and cover 3, like other elements of the relay, are formed of a reinforced plastic material, such as a linen base phenolic material, although any of many other commercially available plastic materials may be suitable. The base 2 is provided with a pair of apertured mounting ears 6 by means of which it can be mounted on a panel or in a switch enclosure.

A plastic bobbin 7, having a substantially square crosssection, is suspended from the cover 3 and disposed within the case 1. At its lower end and somewhat below its upper end, as seen for example in FIG. 3, the bobbin 7 is provided with generally square, outwardly extending flanges 8. An electrical operating coil 3 is wound about the bobbin 7 between the flanges 8. Although the electromagnetic design of the coil may be varied to fulfill particular operating requirements, its polarity and the strength of its magnetic field must, to some extent, be determined by the characteristics of magnetic bias means as will be described.

The bobbin 7 and coil 9 are mounted in a U-shaped magnetically conductive metal support 1%, comprising a generally square baseon which the bobbin 7 rests and a pair of legs which extend upwardly on opposite sides of the bobbin '7 to be turned over the upper flange 8. The base and turned-over legs of the support 10 hold the bob: bin 7 in place with a relatively tight friction fit. As seen most clearly in FIG. 8, the base of the support 10 is provided with a square aperture 11, through which various elements extend as will be described. The bobbin 7 slides easily into the support 10 during assembly, and a cutout portion 12 at one edge of the base of the support 1% receives a boss 13 formed in the bobbin 7 to insure that the bobbin 7 can be inserted into the support 18 in only one selected orientation.

A pair of long assembly screws 14 have their heads recessed in the corners of the cover 3 not occupied by the bolts 4, and are received at their lower ends in threaded apertures at opposite corners of the base of the support 10, as seen in FIG. 8, whereby the support 10, bobbin 7 and coil 9 are suspended from the cover 3 to form a unit. The bolts 4 pass through unthreaded apertures at the remaining corners of the base of the support 10, and this allows the base to be large enough with respect to the interior of the case 51 to properly locate the various elements and restrict chattering or other movement thereof during use.

In addition to supporting and protecting the bobbin 7 and coil 9, the magnetically conductive support 10 serves to complete a magnetic return circuit which increases the efiicicncy of the coil 9.

As can be seen most clearly in FIGS. 3, and 7, the bobbin 7 is provided with four bores 15. of generally rectangular cross-section, the longer axes of the bores 15 extending radially inwardly from the corners of the bobbin- 7 toward its center. The bores 15 are of substantially constant cross-section and extend from the bottom of the bobbin 7 to a point just short of its top where they are closed off by top walls 16. Narrow slits 17 extend through the walls 16 at the radially outer ends of the bores 15. To reduce the weight and cost of the bobbin 7, its remaining portions may be hollowed out and provided with reinforcing ribs as desired.

A switch with magnetically operable contacts, here a dry reed switch 18, is disposed within each bore 15 at the radially outer end thereof to form a cluster of four reed switches 13 disposed in the bobbin 7. Each switch 18 comprises an elongated hermetically sealed, cylindrical glass envelope 19 filled with an inert gas. The radially outer ends of the bores 15 are preferably rounded to conform to the cylindrical configuration of the envelopes 19. A pair of resilient, electrically and magnetically conductive reeds 2t) extend through opposite ends of the envelope 19. Inside the envelope 19, the reeds 2d are flattened to provide normally open or spaced apart, resil lent, overlapping contact ends 21. Outside the envelope 1) the reeds 26' are flattened to provide upper and lower terminals 22. by means of which the switch 18 may be connected into an electrical circuit.

The flattened upper terminal 22 of each switch 18 is received through a corresponding slit 17 with a tight friction fit W-ith the relatively thick unflattened portion of the reed 2% below the terminal 22 serving as an abutment to limit the extent to which the reed Zti may extend through the slit 17. The slits 17 are positioned so as to locate the switches 18 properly at the outer ends of the bores 15, and their tight fit with the terminals 22 allows the bobbin 7 to be held in an upright position during assembly without having the switches 18 fall therefrom, and to restrict lateral or rotational movement of the switches 18 during use. The limitation of upward movement afforded by the thicker unfiattened portion of the reeds 2d simplifies assembly and insures that the switches 18 are inserted fully in the bobbin 7 in proper axial position. If desired, the same limitation of upward movement could be provided with a ribbon-like reed which has no relatively thicker unflattened bearing portion since the upper end of the envelope 19 would itself serve as an abutment to limit upward movement.

A plastic cap member 23, seen most clearly in FIG. 10, is mounted at the bottom of the bobbin 7 by means of a suitably threaded screw 24, and is provided with a generally square, outwardly extending flange 25, seen most clearly in FIGS. 4 and 9. Each corner of the flange 25 is provided with a radial, outwardly opening slot 26. The lower terminal 22 of each switch 18 is received in a corresponding slot 26 with a relatively tight fit to locate and hold the switch 18 at the radially outer end of its bore 15. The upper surface of the flange 25 bears against the unfiattened portions or abutments ofthe reeds 20 to insure tha the switches 18 are inserted'fully into the bores 15, although again this could be accomplished by having the flange 25 bear directly on the lower ends of the envelopes 19.

Vertically slid-ably mounted in each bore 15, radially inwardly of the associated switch 18, that is closer to the center of the bobbin 7, is a magnetic bias means in the form of a bar magnet 27 having glued or otherwise attached to its radially innermost face a rectangular, magnetically conductive keeper 28. Although ordinary bar magnets might be used with the invention, the bar magnets 27 are preferably formed of a transversely magnetized barium ferrite material, since such amagnet is extremely eflicient and is not particularly susceptible to demagnetization by repeated operations of the coil 9. The keepers 23 serve to shield each magnet 27 from the others by providing a magnetic return circuit at the nearest surfaces of the several magnets 27, to afford greater strength since the magnets 27 are themselvesrather fragile, and to serve as guide means bearing on the innermost surface and sides of the slideway formed by the bores 15. The magnets 27 are transversely magnetized at each end, that is, for example, the upper end of each magnet 27 may have a north pole at its radially outermost surface and a south pole at its radially innermost surface while the lower end has, a south pole at its outer surface and a north pole at its inner surface. It is a particularly desirable characteristic of ferrite magnets that they may be transversely magnetized in this manner which insures a strong field for each magnet 27 extending radially outwardly from the center of the bobbin 7 toward an associated switch 18. For an ordinary bar magnet with a north pole at one end and a south pole at the other, the keepers 28 on the inner surface of each magnet 27 could serve as a path of extremely low reluctance and thereby reduce the strength of the magnetic field extending radially outwardly from each magnet 27. With transverse magnetization, however, a strong outwardly extending field between the opposite poles on the outer surface of each magnet 27 is guaranteed.

As stated, the radially inner end of each aperture 15' serves as a slideway for a magnet 27, and along this slideway each magnet 27 may be moved between two positions illustrated in FIG. 3. In FIG. 3, the right hand magnet 27 is in what is referred to herein as an inactive position, at the upper end of its slideway and adjacent the upper half of its switch 18 and effectively removed from the contact ends 21 thereof. The left hand magnet 27 in FIG. 3 is in what is termed herein a biasing position, at about the mid-point of its slideway and directly across the contact ends 21 of its switch 13.

As can be seen most clearly in FIGS. 3, 8, 9 and 10, the cap member 23 is provided at each of its corners with a vertical, tubular spring well 29 extending both above and below the flange 25, with one well 29 positioned directly below the radially inner end of each bore 15. A compression spring 39 is seated in each well 29 and extends substantially into its associated bore 15 when relaxed.

A block-like guide 31, formed of a non-magnetic metal such as brass, is positioned between and engages the upper end of each spring 3% and the lower end of its associated magnet 27. Each guide 31 is provided with a downward- 13/ extending, integrally formed guide pin 32 received in an associated spring 39 and well 29. The springs 39, acting through the guides 31, serve as bias means to urge the magnets 27 upwardly toward their inactive positions. The block-like guides 31 have a guiding fit within the slideways formed by the bores 15 to prevent binding and to provide an adequate bearing area with the magnets 27 and springs 39. The magnets 27 have a relatively long path of travel, and the pins 32, which are long enough so that they are at all times at least partially in the Wells 2%, insure a guided, straight line motion.

As can be seen in FIG. 6, a plunger aperture 33 extends through each wall 16 and is positioned directly above an associated magnet 27. The cover 3 is provided with a downwardly extending, integrally formed plunger block 34 of substantially square cross-section which is positioned over and rests on the walls 16. At each corner of the block 34 there is a cylindrical vertical plunger bore 35 therethrough, with each bore 35 positioned directly over and communicating with an associated aperture 33. As seen most clearly in FIG. 3, each bore 35 has a bottom portion 36 of larger diameter above which it is provided oil its radially outermost side with a keyway 37 that extends to a point near the top of the block 34. Opposite the keyway 37 is a relatively short second lreyway or locking slot 33 that extends upwardly a short distance from the bottom portion 36 of the block 34.

A cylindrical plastic plunger 39, with a key 4t) near but below its upper end, is slidably mounted in each bore 35 and extends downwardly through an associated aperture 33 to rest on the top of a magnet 27. The upper end of each plunger 39 is provided with a screw slot it which serves as a tool engaging means as will be described.

Each side of the cover 3 is recessed as at 42 and serves as a receptacle for a pair of switch terminals 43 which extend downwardly through the cover 3 to terminate above the bobbin 7. At their upper outer ends, the terminals 43 are provided with connecting terminal screws 44. As can best be seen in FIGS. 5 and 6, the terminals 43 are positioned at the corners of the bobbin 7, relatively close to the upper terminals 22 of the switches 18. To guard against short circuits, the bobbin 7 is provided at each corner with a curved upstanding shield 45, as seen most clearly in FIGS. 3, 6 and 10, which is outside of and protects the upper terminal of an associated switch 18.

At the top of the cover 3 there are a pair of coil termirials as with terminal screws 47, which extend downwardly through the cover 3 on opposite sides of the plunger block 34. Above the cover 3, the terminals 46 and screws 47 are positioned above bosses 48 formed between terminals 43 on opposite sides of the cover 3. As can be seen in FIG. 1, connecting wires 49 lead between and connect the coil 9 with the terminals 46. Since the polarity of the coil 9 is important as will be described, the terminals 46 may be differentiated by appropriate markings on the cover 3.

The switches 18 and terminals 43 are preferably connected, by welding or soldering as desired, so that the upper and lower terminals 22 of each switch 18 are con nected to terminals 43 in a single recess 42. This results in each recess 42 containin terminal connections for a particular switch 18 which are shielded and separated from the terminal connections for the remaining switches 13, thus simplifiying connection into external controlled or control circuits since connections for a particular switch 18 are made from but one side of the relay. If desired, the switches 18 may be arbitrarily numbered and these numerals may be marked in the recesses 42 to indicate which switch 13 the terminals 43 therein are connected to. Since each plunger 39 controls the state of an associated switch 13, the same marnings may be applied adjacent ppropriate plunger-s The particular relay shown herein has switches is that are convertible etween normally open and normally closed operation, and its operation may be understood most easily by reference to FIGS. 3 and 10. In FIG. 3, two switches in in diiferent states of operation are shown, and to illustrate the operation more clearly, the center portions of the two switches 13 have been shown rotated ninety degrees. That is, the width of the flattened contact ends 21 normally extends radially outward as in the case of the terminals To show the state of the switches 18 in FIG. 3, however, the ends 21 are shown in positions perpendicular to their actual positions. The right hand switch lb in FIG. 3 is in a usual normally open state, that is with the contact ends 21 of its reeds 20 spaced apart. Because they are magnetically conductive, magnetic flux established by the coil 9 may pass between the contact ends 21 in either direction to operate the switch by developing an attractive force therebetween and causing the contact ends 21 to be drawn together or closed against the resilience of the reeds Ztl so that an electrical circuit through the switch 18 is completed. When the magnetic flux ceases, the resiliency of the reeds 2% causes a return to an open state.

A closing action of a switch 13 will also occur when its magnet 27 is moved into a biasing position, as seen in the case of the left hand magnet 27 shown in FIG. 3. In this position, the magnet 27 is across the contact ends 21 and will establish magnetic flux which will bias the ends ill to cause a closing action and keep the switch 18 closed so long as the coil 9 is inactivated. The coil 9 and magnets 27 in this embodiment of the invention are in magnetic opposition, however, being designed and installed so that the magnetic field of the coil 9 when it is energized is opposite in direction to that of the magnets 27. Thus, when the coil 9 is energized, the flux estab lished by the left hand magnet 27 in FIG. 3 will be cancelled and the natural resiliency of the reeds 2t) will cause the switch 13 to open. When the coil 9 is tie-energized, the magnet 27 will again bias the switch 13 to closed position so that the switch 18 has a normally closed operation.

The ferrite magnets 27 are particularly suitable in a relay formed according to this invention because, as stated above, they are not particularly susceptible to demagnetization by repeated operations of the coil 9. The fact that each magnet 27 is radially inside of its switch 18 increases the distance between it and the coil 9 so. that the magnet 27 is shielded by the switch 18. to. further guard against tie-magnetization.

Since the directions of the flux established by the coil 9 and magnets 27 are important, it is convenient in addition to. marking the terminals 45 to mark one or both ends. of the magnets 27 to be sure they are assembled in proper orientation. Also, it should be apparent that the magnets 27 and coil 9 should be designed so that the strengths of their magnetic fields are approximately equal.

Movement of the magnets 27 between inactive and biasing positions. is effected by means comprising the plungers 39, springs 3t? and their associated elements. The plungers 39 are normally in the position shown to the right in FIG. 3, which may be termed a retracted position. That is, the plunger 39 is in a predetermined rotational position with the key 3,4 ali ned with the keyway 37 whereby the spring 3%, acting through the guide 31, has been freed to push the magnet 2'7 and plunger 39 upwardly, with the magnet 2'7 thus being moved to its inactive position where it is effectively removed from the contact ends 21 of its switch ltl so that it cannot establish a field of sufficient strength to close or otherwise substantially affect the switch is. in its retracted position, the plunger 39 is at the top of the bore 35 where it is visible to serve as a visual indication of the normally open state of its switch 18.

A small screwdriver may then be used to move the plunger 39 to the position seen to the left in FIG. 3, which may be termed an actuating position. That is, the plunger 39 is pushed downwardly to move the magnet 27 against the spring 3% to the biasing position of the magnet 27. The key 40 is thus moved into the bottom portion 36 of the bore 35 which is of larger diameter so that the plunger 39 is freed to be rotated. The plunger 39 is then given a half turn so that the key 46 is aligned with the locking slot 3? and is then released, the spring 36 then pushing the plunger 39 upwardly until the key it) reaches the top of the slot 38. The magnet 27 is then in the position shown to the left in FIG. 3, its biasing position, while the plunger 39 is below the top of the cover 3 to serve as a visual indication that its switch 18 is in a normally closed state.

The slot 33 serves as a means to lock the plunger 39 and associated elements in actuating position and prevent accidental rotation. The ledge formed by the provision of the larger portion 36 in the bore 35 can, however, itself serve as a means to lock the plunger 3% in actuating position once the key 40 is moved out of alignment with the keyway 37, so that the slot 38 can be eliminated if desired. A release and return to the position shown to the right in FIG. 3, can be effected by pushing the plunger 39 downwardly until the key 49 is again in the larger bottom portion 36, giving it a half turn to align the key All with the keyway 37 and releasing it.

In the particular embodiment of the invention shown herein, the magnets 27 are in magnetic opposition to the coil 9 and are movable between inactive positions where they do not afiect their associated switches 18 and biasing positions where they operate to close their associated switches 18. This arrangement is quite simple and especially suitable where it is desired to provide a relay with switches that are convertible between normally open and normally closed operation. simple and highly sophisticated, are, however, easily possible within the scope of the invention. For example, by arranging the coil 9 and magnets 2'7 to be cumulative and lengthening the locking slots 33, the biasing position of the magnets 27 can cause them to have a latching effect rather than a closing effect. That is, the magnets Other arrangements, both see 27 could have biasing positions Where they are not directly across the contact ends 21 of their associated switch 18 but are somewhat. removed so that they do notv establish enough flux to. cause closing but are close enough to the ends 21 so that they will hold them closed after the coil 9 is deenergized, a reverse. pulse in the coil 9: then being usedto clear. the switch 13.

Also, a relay with. somev magnets 27 in. opposition to the coil 9. and some additive could be provided, the magnets 27 being easily reversible end-for-end, to provide for varied manners of operation in response to normal and reverse pulses of the coil 9. If desired, a second slot, similar, to but longer than the slot 38, could be provided with the two slots and the keyway 37 spaced degrees apart. Each magnet 27 could then have two biasing. positions, one across the contact ends 21 of its switch 18 where it exerts a closing effect and the other some what removed so that it exerts a latching effect.

Because of the foregoing and other possible variations, the invention is not intended to be limited to an arrangement wherein, a magnet has a biasing position where it closes an associated switch, the term biasing position being intended, to cover any position wherein the magnet biases, or exerts a substantial effect, closing, latching and the like, on the contacts of an associated switch.

A number of other variations are possible within the scope of the invention. For one example, the key-keyway arrangement shown herein could be altered by having a keyway in the plunger 35% and a key in the bore 35. Also, by lengthening the bores 15 the magnets 27 could be arranged so that their inactive positions are below the contact ends 21, and the springs 31) would then urge the magnets 2? toward biasing positions while the plungers 39 would be used to move the magnets 27 toward their inactive positions. Further, other suitable switches with magnetically operable contacts could be substituted for the dry reed switches 13. Still further, normally closed magnetically operable switches could be used without departure from the invention. Because of the many possible variations, the specific embodiment of the invention shown and described herein is not intended in any way to limit the invention, which is not to be limited except insofar as limitations appear in the appended claims.

We claim:

1. In a relay, the combination comprising: a plurality of switches with magnetically operable contacts; an operating coil in proximity to and adapted to operate all of the switches simultaneously; a plurality of magnetic bias means, one associated with each switch, each being operatively associated with and adapted to affect the switch contacts of its associated switch, each magnetic bias means being movable between inactive and biasing positions with respect to its switch, the magnetic bias means being operatively independent of one another so that each is operatively effective only with respect to its associated switch; and a plurality of independently operable operating means, there being one such means for each magnetic bias means, to move the magnetic bias means between said positions.

2. In a relay the combination comprising: a case; a cover for the case having a plunger block depending therefrom with a plurality of vertical cylindrical bores'thcrethrough, each of said bores having a bottom portion of relatively larger diameter, a first keywayextending upwardly from the bottom portion to terminate near the top of the bore, and a second keyway on the opposite side of the bore from the first keyway that extends upwardly a short distance above the bottom portion of the bore; a plurality of cylindrical plungers one of which is slidably mounted in each of the bores, each of said .plungers having a tool engaging means at its upper end and an 'outwardly extending key slightly below its upper end that fits within the first and second kcyways; a bobbin disposed within the case below the cover and plunger block, said bobbin having a plurality of vertical switch bores therethrough, one of said switch bores being disposed below each of the plungers; a plurality of elongated, vertically disposed switches, one mounted in each of the switch bores of the bobbin, each of said switches having resilient normally open magnetically operable contact ends near its longitudinal center; an operating coil disposed about the bobbin that is operable to close the switches; a plurality of magnets that are in magnetic opposition to the coil, one of said magnets being slidably mounted in each of the switch bores directly under an associated plunger, each of said magnets being movable between an upper inactive position where it is effectively removed from the contact ends of its associated switch and a lower biasing position where it is magnetically linked with the contact ends of its associated switch and operates to close the contact ends; a cap member mounted on the bottom of the bobbin; and a plurality of bias means extending upwardly from the cap member, one bias means being positioned in each of the switch bores and being operable to urge an associated magnet upwardly toward its inactive position.

3. In a relay the combination comprising: a block-like supporting member having a plurality of spaced bores therethrough; a plurality of switches with magnetically operable contacts, one switch being disposed Within each bore; an operating coil disposed in operating proximity to all of the switches and adapted to be energized to operate all of the switches simultaneously; a plurality of magnets, one in each bore, each of which is slidable within its bore and alongside its switch between a biasing position where it affects the switch contacts and an inactive position where it is effectively removed from the contacts, the several magnets being separated so that each is operative only with respect to its associated switch; and a plurality of independent operating means, one for each magnet, to slide the magnets between their said positions.

4. In a relay the combination comprising: a bobbin having a plurality of circumferentially spaced bores therethrough; a plurality of switches with magnetically operable contacts, one disposed in each bore; an operating coil encircling the bobbin and adapted to be energized to operate all of the switches simultaneously; a plurality of magnets, one disposed in each bore radially inwardly of an associated switch, each magnet being slidable along side its switch between an inactive position where it is effectively removed from the switch contacts and a biasing position where it affects the switch contacts, the magnets being provided with keepers of magnetic material along their radially innermost faces to provide a magnetic return circuit for each magnet shielding it from the other magnets; and a plurality of independent operating means, one for each magnet, to slide the magnets between their said positionsi 5. In a relay the combination comprising: a bobbin having a plurality of circumferentially spaced vertical bores therethrough; a plurality of elongated switches with magnetically operable contacts near their longitudinal centers, one switch being vertically disposed in each bore; an operating coil encircling the bobbin that is adapted to be energized to operate all of the switches simultaneously; a plurality of magnets, one disposed in each bore radially inwardly of an associated switch, each magnet being vertiearly slidable in its bore alongside the associated switch between an inactive position where it is effectively removed from the switch contacts and a biasing position where it affects the switch contacts, the magnets being spaced from one another so that each magnet is operatively effective with respect only to its associated switch; plunger block means atop the bobbin and having a plurality of bores therethrough that are in alignment with the bobbin bores; a plurality of plungers slidably received in the plunger block bores and engageable with the tops of the magnets, the plungers being adapted to be depressed to an actuating position to slide the magnets to one of their positions; bias means engageable with the lower ends of the magnets to urge them toward their other positions; and key and keyway means for the plungers and plunger block bores to hold the plungers in their actuating positions.

6. In a relay the combination comprising: a supporting member including a slideway; an elongated switch with magnetically operable contacts disposed parallel to and adjacent the slideway; a magnet disposed in and slidable along the slideway to be movable therein between i an inactive position where it is effectively removed from the switch contacts and a biasing position where it atfects the switch contacts; bias means at one end of the slideway engaging the magnet to urge it toward one of its said positions; a plunger block at the other end of the slidewa said plunger block having a cylindrical bore therethrough that is parallel to and aligned with the slideway, said bore having an inner end closest to the slideway that is of relatively larger diameter and an outer end and having a first keyway extending outwardly from said inner end to terminate near the outer end and a second keyway circumferentially spaced from the first keyway that extends outwardly from said inner end a substantially shorter distance than the first keyway; and a cylindrical plunger rotatably and slidably disposed in the bore, said plunger having an outer end provided with tool engaging means, an outwardly extending key near its outer end that fits within said first and second keyways and an inner end engageable with the magnet to move the magnet toward the other of its said positions when the plunger is depressed, said plunger serving to hold the magnet in said other position when the key is in the second keyway.

References Cited by the Examiner UNITED STATES PATENTS 2,919,322 12/59 Dietrich 200-87 2,999,915 9/61 Pfleiderer et al. 200-87 3,046,370 7/62 Adams et al. 200-87 3,056,868 10/62 Jacobson et al. 20087 3,129,680 4/64 Doerner 200--87 BERNARD A. GILHEANY, Primary Examiner. ROBERT K. SCHAEFER, Examiner. 

1. IN A RELAY, THE COMBINATION COMPRISING: A PLURALITY OF SWITCHES WITH MAGNETICALLY OPERABLE CONTACTS; AN OPERATING COIL IN PROXIMITY TO AND ADAPTED TO OPERATE ALL OF THE SWITCHES SIMULTANEOUSLY; A PLURALITY OF MAGNETIC BIAS MEANS, ONE ASSOCIATED WITH EACH SWITCH, EACH BEING OPERATIVELY ASSOCIATED WITH AND ADAPTED TO EFFECT THE SWITCH CONTACTS OF ITS ASSOCIATED SWITCH, EACH MAGNETIC BIAS MEANS BEING MOVABLE BETWEEN INACTIVE AND BIASING POSITIONS WITH RESPECT TO ITS SWITCH, THE MAGNETIC BIAS MEANS BEING OPERATIVELY INDEPENDENT OF ONE ANOTHER SO THAT EACH IS OPERATIVELY EFFECTIVE ONLY WITH RESPECT TO ITS ASSOCIATED SWITCH; AND A PLURALITY OF INDEPENDENTLY OPERABLE OPERATING MEANS, THERE BEING ONE SUCH MEANS FOR EACH MAGNETIC BIAS MEANS TO MOVE THE MAGNETIC BIAS MEANS BETWEEN SAID POSITIONS. 